U.S. patent number 8,363,398 [Application Number 12/910,852] was granted by the patent office on 2013-01-29 for electronic device with heat dissipation casing.
This patent grant is currently assigned to Hon Hai Precision Industry Co., Ltd.. The grantee listed for this patent is Zeu-Chia Tan. Invention is credited to Zeu-Chia Tan.
United States Patent |
8,363,398 |
Tan |
January 29, 2013 |
Electronic device with heat dissipation casing
Abstract
An electronic device includes a casing, an electronic component
accommodated in the casing; and a composite heat conductive layer
between the casing and the electronic component. The composite heat
conductive layer includes a graphite layer and a thermal pad layer
between the electronic component and the graphite layer. The
thermal pad layer is attached to the electronic component. The
graphite layer is attached to an inner surface of the casing. The
graphite layer is located between the casing and the thermal pad
layer. Heat conductive efficiency of the graphite layer along a
horizontal spreading direction thereof exceeds that along a
vertical thickness direction thereof. A surface area of the
graphite layer is not less than that of the electronic component.
Heat generated by the electronic component is evenly transferred
and is spread to the casing via the graphite layer of the composite
heat conductive layer.
Inventors: |
Tan; Zeu-Chia (Taipei Hsien,
TW) |
Applicant: |
Name |
City |
State |
Country |
Type |
Tan; Zeu-Chia |
Taipei Hsien |
N/A |
TW |
|
|
Assignee: |
Hon Hai Precision Industry Co.,
Ltd. (New Taipei, TW)
|
Family
ID: |
45817587 |
Appl.
No.: |
12/910,852 |
Filed: |
October 24, 2010 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20120069515 A1 |
Mar 22, 2012 |
|
Foreign Application Priority Data
|
|
|
|
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Sep 16, 2010 [TW] |
|
|
099131355 A |
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Current U.S.
Class: |
361/679.54;
361/704; 361/708; 361/707 |
Current CPC
Class: |
G06F
1/203 (20130101) |
Current International
Class: |
H05K
7/20 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Chervinsky; Boris
Attorney, Agent or Firm: Altis Law Group, Inc.
Claims
What is claimed is:
1. An electronic device comprising: a casing; an electronic
component accommodated in the casing; and a composite heat
conductive layer between the casing and the electronic component,
the composite heat conductive layer comprising a graphite layer and
a thermal pad layer, the graphite layer being a sheet of graphite;
wherein the thermal pad layer is attached to a top surface of the
electronic component, the graphite layer is attached to an inner
surface of the casing, the thermal pad layer is located between the
electronic component and the graphite layer, the graphite layer is
located between the casing and the thermal pad layer, a heat
conductive coefficient of the graphite layer along a horizontal
spreading direction thereof exceeds that along a vertical thickness
direction thereof, and a surface area of the graphite layer is not
less than that of the top surface of the electronic component, such
that heat generated by the electronic component is evenly
transferred and spread to the casing via the graphite layer of the
composite heat conductive layer.
2. The electronic device of claim 1, wherein a ratio between a
length of the graphite layer and a length of the top surface of the
electronic component is in the range of about 1.5:1 to about
1:1.
3. The electronic device of claim 2, wherein a ratio between a
width of the graphite layer and a width of the top surface of the
electronic component is in the range of about 1.5:1 to about
1:1.
4. The electronic device of claim 1, wherein the surface area of
the graphite layer is not less than that of the thermal pad
layer.
5. The electronic device of claim 1, wherein a ratio between a
length of the graphite layer and a length of the thermal pad layer
is in the range of about 1.5:1 to about 1:1.
6. The electronic device of claim 5, wherein a ratio between a
width of the graphite layer and a width of the thermal pad layer is
in the range of about 1.5:1 to about 1:1.
7. The electronic device of claim 1, wherein the thermal pad layer
is a layer of thermal conductive film or a layer of thermal
conductive grease.
8. The electronic device of claim 1, wherein the thermal pad layer
is an electrical insulator between the graphite layer and the
electronic component.
9. The electronic device of claim 1, wherein the electronic device
is a notebook computer.
10. The electronic device of claim 1, wherein the sheet of graphite
is continuous.
11. The electronic device of claim 1, wherein the graphite layer is
directly attached to the inner surface of the casing.
12. An electronic device comprising: a casing; an electronic
component accommodated in the casing; and a composite heat
conductive layer between the casing and the electronic component,
the composite heat conductive layer comprising a graphite layer and
a thermal pad layer, the graphite layer being a sheet of graphite;
wherein the thermal pad layer is attached to a top surface of the
electronic component, the graphite layer is attached to an inner
surface of the casing, the thermal pad layer is located between the
electronic component and the graphite layer, the graphite layer is
located between the casing and the thermal pad layer, a heat
conductive coefficient of the graphite layer along a direction from
the thermal pad to the casing exceeds that along a direction
perpendicular to the inner surface of the casing, and a surface
area of the graphite layer is not less than that of the top surface
of the electronic component, such that heat generated by the
electronic component is evenly transferred and spread to the casing
via the graphite layer of the composite heat conductive layer.
13. The electronic device of claim 12, wherein the sheet of
graphite is continuous.
14. The electronic device of claim 12, wherein the graphite layer
is directly attached to the inner surface of the casing.
Description
BACKGROUND
1. Technical Field
The present disclosure generally relates to electronic devices, and
particularly to an electronic device having a composite heat
conductive layer for transferring heat of an electronic component
to a casing thereof for heat dissipation.
2. Description of Related Art
Electronic components for electronic devices, such as CPUs (central
processing units) for computers, generate heat in operation. The
heat must be dissipated immediately, to avoid overheating and
damaging the electronic component. A heat sink is mounted in a
casing of the electronic device and thermally attached to the
electronic component to dissipate heat from the electronic
component.
However, the trend towards miniaturization of electronic devices
leaves insufficient space therein for accommodating the heat sink.
Thermally attaching the electronic component to the casing of the
electronic device makes use of the casing for heat dissipation.
Generally, the electronic component has high heat density. If the
electronic component of the electronic device is attached to the
casing of the electronic device, a hot spot is formed on the
casing, adversely affecting the heat conductive efficiency between
the electronic component and the casing, and making use of the
electronic device uncomfortable for the user.
Accordingly, what is needed is an electronic device which can
overcome the described limitations.
BRIEF DESCRIPTION OF THE DRAWINGS
Many aspects of the embodiment can be better understood with
reference to the following drawings. The components in the drawings
are not necessarily drawn to scale, the emphasis instead placed
upon clearly illustrating the principles of the present disclosure.
Moreover, in the drawings, like reference numerals designate
corresponding parts throughout the views.
FIG. 1 is an isometric, assembled view of an electronic device
according to an embodiment of the present disclosure.
FIG. 2 is a schematic view of a heat dissipation structure of the
electronic device of FIG. 1.
DETAILED DESCRIPTION
FIG. 1 shows an electronic device 200 according to an embodiment of
the present disclosure. In the embodiment, the electronic device
200 is a notebook computer. The electronic device 200 includes a
mainframe 21, and a display unit 22 rotatably mounted on the
mainframe 21. The mainframe 21 includes a casing 211, an electronic
component 212 (referring to FIG. 2) received in the casing 211, and
a composite heat conductive layer 23 received in the casing 211 and
disposed between the electronic component 212 and the casing 211.
The electronic component 212 may for example include a number of
processors or random access memory (RAM). The electronic component
212 is located under the composite heat conductive layer 23. During
operation of the electronic device 200, heat generated by the
electronic component 212 is evenly transferred to the casing 211
with the composite heat conductive layer 23 and is dissipated by
the casing 211.
Referring to FIG. 2, the composite heat conductive layer 23
includes a graphite layer 231 and a thermal pad layer 232. The
graphite layer 231 is thermally attached to an inner surface of the
casing 211. The thermal pad layer 232 is thermally attached to the
electronic component 212.
The graphite layer 231 is a sheet of graphite. The graphite layer
231 has good heat spreading capability, i.e. heat conductive
efficiency of the graphite layer 231 along a horizontally spreading
direction thereof exceeds that along a vertically thickness
direction thereof. Heat conductive efficiency of the graphite layer
231 along the horizontally spreading direction thereof is about 450
W/mK to about 750 W/mK. The heat conductive efficiency of a
metallic casing along a horizontally spreading direction thereof is
approximately 50 W/mK, and heat conductive efficiency of a thermal
pad along a horizontally spreading direction thereof is about 1
W/mK to about 3 W/mK. Therefore, the heat spreading capability of
the graphite layer 231 is much greater than that of metallic casing
and thermal pad. A surface area of the graphite layer 231 is not
less than that of a top surface of the electronic component 212
which faces the casing 211. In one embodiment, the ratio between a
length of the graphite layer 231 and a length of the electronic
component 212 is about 1.5:1 to about 1:1. In one embodiment, the
ratio between a width of the graphite layer 231 and a width of the
electronic component 212 is about 1.5:1 to about 1:1. In addition,
the graphite layer 231 can absorb electromagnetic radiation
generated by the electronic component 212 during operation.
The thermal pad layer 232 is disposed between the graphite layer
231 and the top surface of the electronic component 212. The
thermal pad layer 232 is a layer of thermal conductive film or a
layer of thermal conductive grease, which decreases thermal
resistance between the graphite layer 231 and the electronic
component 212. The thermal pad layer 232 also acts as a strength
buffer layer to avoid damage to the graphite layer 231 and the
electronic component 212. In addition, the thermal pad layer 232 is
an electrical insulator between the graphite layer 231 and the
electronic component 212. A surface area of the thermal pad layer
232 is not less than that of the electronic component 212 but not
larger that that of the graphite layer 231. In one embodiment, the
ratio between a length of the graphite layer 231 and a length of
the thermal pad layer 232 is about 1.5:1 to about 1:1. In one
embodiment, the ratio between a width of the graphite layer 231 and
a width of the thermal pad layer 232 is about 1.5:1 to about 1:1.
If the graphite layer 231 and the thermal pad layer 232 have
approximately the same length and width, the graphite layer 231 has
the best heat spreading effect.
During operation of the electronic device 200, heat generated by
the electronic component 212 is transferred to the graphite layer
231 via the thermal pad layer 232. The heat is evenly transferred
and spread to the casing 211 of the electronic device 200 via the
graphite layer 231. Because the graphite layer 232 has good heat
spreading capability, the heat distribution on the casing 211 is
even, and the hot spot on the casing 211 is eliminated.
It is to be understood that even though numerous characteristics
and advantages of the embodiment(s) have been set forth in the
foregoing description, together with details of the structures and
functions of the embodiment(s), the disclosure is illustrative
only, and changes may be made in detail, especially in matters of
shape, size, and arrangement of parts within the principles of the
invention to the full extent indicated by the broad general meaning
of the terms in which the appended claims are expressed.
* * * * *